diff --git a/.gitignore b/.gitignore
index ccdd4eb..d8a40da 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ target/
 .worktrees/
 extension/node_modules/
 extension/dist/
+extension/dist-firefox/
 extension/wasm/
diff --git a/extension/manifest.firefox.json b/extension/manifest.firefox.json
new file mode 100644
index 0000000..b74332f
--- /dev/null
+++ b/extension/manifest.firefox.json
@@ -0,0 +1,36 @@
+{
+  "manifest_version": 3,
+  "name": "idfoto",
+  "version": "0.1.0",
+  "description": "Two-factor encrypted password manager",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "idfoto@adlee.work",
+      "strict_min_version": "128.0"
+    }
+  },
+  "permissions": ["storage", "activeTab", "clipboardWrite"],
+  "host_permissions": ["<all_urls>"],
+  "background": {
+    "scripts": ["service-worker.js"]
+  },
+  "action": {
+    "default_popup": "popup.html",
+    "default_icon": {
+      "16": "icons/icon-16.png",
+      "48": "icons/icon-48.png",
+      "128": "icons/icon-128.png"
+    }
+  },
+  "content_scripts": [{
+    "matches": ["<all_urls>"],
+    "js": ["content.js"],
+    "run_at": "document_idle"
+  }],
+  "content_security_policy": {
+    "extension_pages": "script-src 'self' 'wasm-unsafe-eval'; object-src 'self'"
+  },
+  "web_accessible_resources": [{
+    "resources": ["setup.html", "setup.js", "styles.css", "idfoto_wasm_bg.wasm", "idfoto_wasm.js"]
+  }]
+}
diff --git a/extension/package.json b/extension/package.json
index 96eca1d..f36c3dd 100644
--- a/extension/package.json
+++ b/extension/package.json
@@ -4,9 +4,11 @@
   "private": true,
   "scripts": {
     "build": "webpack --mode production",
+    "build:firefox": "webpack --config webpack.firefox.config.js --mode production",
+    "build:all": "npm run build:wasm && npm run build && npm run build:firefox",
     "dev": "webpack --mode development --watch",
-    "build:wasm": "wasm-pack build ../crates/idfoto-wasm --target web --out-dir ../../extension/wasm",
-    "build:all": "npm run build:wasm && npm run build"
+    "dev:firefox": "webpack --config webpack.firefox.config.js --mode development --watch",
+    "build:wasm": "wasm-pack build ../crates/idfoto-wasm --target web --out-dir ../../extension/wasm"
   },
   "devDependencies": {
     "@types/chrome": "^0.1.40",
diff --git a/extension/webpack.firefox.config.js b/extension/webpack.firefox.config.js
new file mode 100644
index 0000000..c7fe4c6
--- /dev/null
+++ b/extension/webpack.firefox.config.js
@@ -0,0 +1,36 @@
+const path = require('path');
+const CopyPlugin = require('copy-webpack-plugin');
+
+module.exports = {
+  entry: {
+    'service-worker': './src/service-worker/index.ts',
+    popup: './src/popup/popup.ts',
+    content: './src/content/detector.ts',
+    setup: './src/setup/setup.ts',
+  },
+  output: {
+    path: path.resolve(__dirname, 'dist-firefox'),
+    filename: '[name].js',
+    clean: true,
+  },
+  resolve: {
+    extensions: ['.ts', '.js'],
+  },
+  module: {
+    rules: [{ test: /\.ts$/, use: 'ts-loader', exclude: /node_modules/ }],
+  },
+  plugins: [
+    new CopyPlugin({
+      patterns: [
+        { from: 'manifest.firefox.json', to: 'manifest.json' },
+        { from: 'src/popup/index.html', to: 'popup.html' },
+        { from: 'src/popup/styles.css', to: 'styles.css' },
+        { from: 'setup.html', to: '.' },
+        { from: 'icons', to: 'icons' },
+        { from: 'wasm/idfoto_wasm_bg.wasm', to: '.' },
+        { from: 'wasm/idfoto_wasm.js', to: '.' },
+      ],
+    }),
+  ],
+  experiments: { asyncWebAssembly: true },
+};